Family studies and genetic linkage marker studies are proceeding. In childhood and adolescence, offspring of bipolar patients did not show increased frequency of affective disorders as compared with offspring of controls, although they do in adulthood. A schizophrenia family study is underway. In a large Alzheimer's pedigree, new polymorphisms have been identified, and confirmed by Mendelian transmission in the pedigree. A new linkage of a fibroblast polymorphism to a serum polymorphism was identified. Muscarinic receptors on fibroblasts were studied in additional ill and well relatives of affective disorders patients, with ill relatives showing higher density than well relatives. This may be a genetic marker of vulnerability for affective disorders. The molecular genetics laboratory is proceeding with screening for polymorphisms of genes for various neuropeptides. The brain hexokinase gene was identified from a cDNA library.